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FDA Panel to Review Abbott's XIENCE™ V
Drug-Eluting Stent

November 29 Meeting Follows Last Month's Recommendation of
Medtronic's Endeavor® Drug-Eluting Stent;

November 5, 2007 -- Abbott announced this morning that the U.S. Food and Drug Administration (FDA) has confirmed a Circulatory Systems Devices Advisory Panel meeting on November 29, 2007, to review the company's Premarket Approval (PMA) submission for the XIENCE™ V Everolimus Eluting Coronary Stent System. The PMA was filed on June 1, 2007.

While the FDA is not obligated to follow the recommendations of its Advisory Panels, the agency usually does so. Such a review for Abbott's stent has been a topic of speculation in the interventional cardiology community for some time, especially on the heels of the same Panel's review and unanimous recommendation last month of Medtronic's Endeavor® drug-eluting stent.

Currently the only FDA-approved drug-eluting stents are the Cypher® from Cordis, a division of Johnson & Johnson, and the Taxus®, made by Boston Scientific. Both have been on the U.S. market since 2003 and 2004 respectively, so there is much anticipation about two new second-generation drug-eluting stents becoming available. Medtronic is hoping to launch Endeavor in the next few months; Abbott says it anticipates launch in the first half of 2008, pending FDA approval. Both stents have been available in Europe for some time: Medtronic's Endeavor received the European CE Mark approval in 2005; Abbott's Xience V became available in Europe a little over a year ago.

Both newer stents make use of "imus" drugs, relatives of sirolimus, the immunosuppressant drug used on the Cypher stent. Abbott is using everolimus and Medtronic's choice is zotarolimus or ABT-578, oddly enough a drug manufactured by Abbott. To further blur company lines, Abbott's Xience V stent is also sold by Boston Scientific, under the name "Promus" -- this co-marketing arrangement was part of the January 2006 Guidant acquisition agreement made between the companies.

Without question, the introduction of two new stents will increase the number of players in what has been a shrinking market for drug-eluting stents -- down over a billion dollars worldwide, due to questions about safety and the issue of late stent thrombosis, as well as disputes over whether the newer drug-eluting stents are really worth the cost, whether the difference in performance when compared with bare-metal stents is really as great as originally thought. Both Medtronic and Abbott have emphasized these issues of safety and efficacy in their submissions to the FDA.

Endeavor's Late Loss and Long Term Data
While randomized clinical trial outcomes for the Endeavor show a slightly higher amount of "late loss" than the rival Taxus stent, many physicians feel this is not necessarily a problem. Late loss is the amount of tissue regrowth inside the stent and subsequent reduction in diameter. At a symposium last month, sponsored by Medtronic during the TCT meeting, it was shown that below a certain threshold level, one that the Endeavor is well under, late loss does not seem to translate to an increase in clinical events, such as the need for repeat procedures, heart attack or death. In fact some physicians feel that "a little late loss is not a bad thing" and that it may indicate improved healing, covering of the stent with healthy endothelial cells and a lower risk of late stent thrombosis. Indeed, the safety profile of the Endeavor has borne this out and one feature of the Medtronic submission that the FDA panel liked was the large number of patients enrolled in the Endeavor studies (over 2,000) and the long-term followup (2 and 3 year data were available). Low numbers and lack of followup in early drug-eluting stent trials (Cypher and Taxus) were key criticisms made during the FDA December stent safety panel hearings

Abbott's Superior Results Against Taxus
Abbott comes to the FDA Panel with somewhat shorter followup (out to 2 years) and smaller total numbers of patients enrolled than Medtronic's Endeavor, but with data showing significant superiority to the market leader: Boston Scientific's Taxus stent. For those who think late loss is in fact an indicator, Abbott's Xience V showed a 50% reduction in late loss over Taxus at 8 months. Additionally, and impressive to many, Abbott reported that XIENCE V demonstrated clinical superiority to TAXUS with a significant 43 percent reduction in Major Adverse Cardiac Events (MACE) compared to TAXUS at one year -- their PMA submission to the FDA is the first one to show that a drug-eluting stent is superior in these areas to the current market leading device.

As these newer stents make their way to market, research has been ongoing into newer devices. One promising idea that has generated much excitement with its early results is the bioabsorable stent. Both Abbott and German manufacturer Biotronik have been working on stents that will hold open the artery after balloon angioplasty, deliver a dose of drugs to keep blockages from growing back, and then after six months or so will be reabsorbed into the body, leaving no trace.